隧道高位穿越巨型溶洞处置及防护方案研究

Study on treatment and protection scheme of tunnel crossing from the upper part of giant karst cave

巨型溶洞岩溶地质情况复杂,严重影响隧道工程的开展,隧道高位穿越巨型溶洞处置难度大,防护工作不易开展,选择合适的处置及防护方案是保证隧道运营、施工安全的重要基础。文章依托黔张常铁路高山隧道高位穿越巨型溶洞项目,针对因溶洞空腔巨大、周壁稳定性差、落石风险高等不利因素所造成的施工处置难题,在详细研究国内11个巨型溶洞处置方案的基础上,制定了线路绕避、回填和桥跨3类共11种巨型溶洞处置方案,经过初步分析确定了回填处置方案,进一步对比4种回填方案后选用洞砟回填+上部注浆的处置方法。同时,为保证施工安全,系统总结了国内巨型溶洞施工安全防护技术,并以此为基础提出了高山隧道巨型溶洞施工安全防护措施,隧道最终顺利通过巨型溶洞。

The karst geological conditions of the giant caves are complicated,which seriously affects the development of the tunnel project.It is very difficult to treat the tunnel passing through the upper part of the giant cave,and the protection work is not easy to carry out.Choosing appropriate treatment and protection scheme is an important foundation to ensure the safety of tunnel operation and construction.This paper relies on the project of Qian-Zhang-Chang Railway Gao-Shan Tunnel which crossing from the Upper Part of Giant Karst Cave.Aiming at the problems of construction treatment caused by unfavorable factors such as huge cavities,poor stability of surrounding rock and high risk of falling rocks,on the basis of a detailed study of 11 treatment schemes for giant karst caves in China,11 treatment schemes of giant karst caves in three categories of rerouting around,backfilling and bridge crossing were formulated.After preliminary analysis,the treatment scheme of backfilling was determined.After a detailed comparison of the four backfilling schemes,the treatment method of ballast backfilling and upper grouting is finally selected.At the same time,in order to ensure the construction safety,the safety protection technology for the construction of giant karst caves in China is systematically summarized.Based on this,the safety protection measures for the construction of giant karst caves in the Gaoshan Tunnel are put forward and the tunnel eventually passed through the giant karst cave successfully.